Sudoku

Sudoku is the classic free online number puzzle, playable in your browser with no download and no sign-up. Fill the 9×9 grid so every row, column, and 3×3 box contains the digits 1 to 9 exactly once. Choose Easy, Medium, or Hard, use pencil-mark notes to plan, and race your own best time on phone or desktop.

How to play

• Pick a difficulty: Easy, Medium, or Hard.
• Tap a cell, then tap a number from 1 to 9 to place it.
• Each row, column, and 3×3 box must hold every digit 1–9 with no repeats.
• Turn on Notes to add small pencil marks for candidate numbers.
• On a keyboard, arrow keys move, 1–9 fill, Backspace erases, and N toggles notes.
• Fill the whole grid correctly to solve the puzzle and stop the timer.

Start with the rows, columns, and boxes that are already most filled — they leave the fewest options and give you free placements. When you are stuck, pencil in every candidate for a cell, then look for a digit that can go in only one spot within a row, column, or box. The grid highlights conflicts and matching numbers, so lean on those cues instead of guessing.

More about Sudoku

Despite the Japanese name, Sudoku descends from the Latin square studied by Swiss mathematician Leonhard Euler and from Number Place, published in a U.S. puzzle magazine in 1979. It took its modern form and name in Japan in the 1980s and became a global craze after newspapers began printing it in 2004. A proper Sudoku has exactly one solution reachable by logic alone — no guessing is ever required.

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